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+.\" Copyright (C) 2021 Stefan Roesch <shr@fb.com>
+.\"
+.\" SPDX-License-Identifier: LGPL-2.0-or-later
+.\"
+.TH io_uring_register_buffers 3 "November 15, 2021" "liburing-2.1" "liburing Manual"
+.SH NAME
+io_uring_register_buffers \- register buffers for fixed buffer operations
+.SH SYNOPSIS
+.nf
+.B #include <liburing.h>
+.PP
+.BI "int io_uring_register_buffers(struct io_uring *" ring ",
+.BI "                              const struct iovec *" iovecs ",
+.BI "                              unsigned " nr_iovecs ");"
+.PP
+.BI "int io_uring_register_buffers_sparse(struct io_uring *" ring ",
+.BI "                              unsigned " nr_iovecs ");"
+.fi
+.SH DESCRIPTION
+.PP
+The
+.BR io_uring_register_buffers (3)
+function registers
+.I nr_iovecs
+number of buffers defined by the array
+.I iovecs
+belonging to the
+.IR ring .
+
+The
+.BR io_uring_register_buffers_sparse (3)
+function registers
+.I nr_iovecs
+empty buffers belonging to the
+.IR ring .
+These buffers must be updated before use, using eg
+.BR io_uring_register_buffers_update_tag (3).
+
+After the caller has registered the buffers, they can be used with one of the
+fixed buffers functions.
+
+Registered buffers is an optimization that is useful in conjunction with
+.B O_DIRECT
+reads and writes, where it maps the specified range into the kernel once when
+the buffer is registered rather than doing a map and unmap for each IO
+every time IO is performed to that region. Additionally, it also avoids
+manipulating the page reference counts for each IO.
+
+.SH RETURN VALUE
+On success
+.BR io_uring_register_buffers (3)
+and
+.BR io_uring_register_buffers_sparse (3)
+return 0. On failure they return
+.BR -errno .
+.SH SEE ALSO
+.BR io_uring_get_sqe (3),
+.BR io_uring_unregister_buffers (3),
+.BR io_uring_register_buf_ring (3),
+.BR io_uring_prep_read_fixed (3),
+.BR io_uring_prep_write_fixed (3)